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A visualization of the density of the radiowaves in Montreal made in 2012 by Jean-Pierre Aube for the Electrosmog World Tour project. (courtesy Jean-Pierre Aube)

A visualization of the density of radiowaves in Istanbul made in 2012 by Jean-Pierre Aube for the Electrosmog World Tour project. The lighter the colour, the more powerful the frequency. (Courtesy Jean-Pierre Aube)

A visualization of the radiowaves in Mumbai made in 2012 by Jean-Pierre Aube for the Electrosmog World Tour project. (Courtesy Jean-Pierre Aube)

But rather than safety, it’s the value of the intangible space that intrigues him most.

Even small sections are worth billions of dollars, as wireless carriers try to snap up pieces of strictly regulated and increasingly saturated airwaves.

The last Industry Canada auction for a bit of the electromagnetic spectrum raised $4.25 billion. The next, postponed until early next year, could rake in just as much for a valuable low frequency that would allow cellphones to work better in poor-coverage areas like elevators and underground garages — lower frequencies have a longer range and easily penetrate walls.

Turning the dial through the frequencies starts with the unwanted radio waves emitted by power lines, known as ELFs, or extremely low frequencies.

On the lower end are frequencies dedicated to maritime and aeronautical navigation and AM radio (535KHz to 1705KHz).

Then come those allocated to amateur radio users, the National Research Council time signal and cordless phones.

TV channels operate between 54MHz and 700MHz, broadcasting off the top of the CN Tower. There is space for 100 FM radio stations between 88MHz and 108MHz.

Cellphone signals are very weak and short range, says Elvino Sousa, a professor in the University of Toronto’s department of electrical and computer engineering. That’s why there are so many towers — 2,400 in the GTA. An antenna will usually service a “cell” of one kilometre or less. There are more downtown because there is “more crowded usage.”

It’s a similar story with Wi-Fi routers, he says. A quick scan of the U of T campus near his office reveals dozens of the networks, he says. According to Statistics Canada, 8.1 per cent of Canadian households had a wireless Internet connection in 2011, and the number is growing.

With the spectrum increasingly congested, there has been a major research focus on making the signals more efficient so more can fit, says Sousa, who likes to compare the spectrum to Toronto real estate.

When there is no more space left to grow outwards, he says, you starting building up.

Aubé wants people to be more aware of this valuable resource swirling around us.

With a device and software of his own making (cobbled together using an ultra-wide band radio with a USB port and a modified antenna) he scanned through a range of frequencies in Montreal. The computer recorded slivers of audio and the strength of the thousands of frequencies.

He repeated this in Mumbai, Helsinki, Tallin, Hong Kong, Istanbul, Berlin and San Francisco.

The result is images and videos that show the density of urban airwaves.

You can tell things about a city from just looking at the visualizations, he says. “Helsinki has much more in the higher frequencies, which mean newer technologies like cellphones. In Estonia you have much more in the lower frequencies — for older technology.”

Wireless technologies are going more and more into our cities, adds Aubé, to explain his fascination with the airwaves. “It’s like it’s the only thing in the economy that’s going well — iPhones and such — so from that I know that we’re in it whether we want it or not.”

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